Circuit breaker



' Oct. 5, 1943. w H. WOODS 12,331,012

' CIRCUIT BREAKER Filed Nov. 13, 1941 2 Sheets-Sheet l Oct. 5, 1943. Wn H. woons CIRCUIT BREAKER Filed Nov. 13, 1941 2 Sheets-Sheet 2 A m Mw m m m WH. u

Wiliam BY f// l Patented o. A5, v194?.

CIRCUIT BREAKER William H. Woods, Garden City, Mich., assigner to Square D Company, Detroit, Mich., a corporation of Michigan Application November 13, 1941, Serial No. 418,904

" 8 Claims.

This invention relates to devices for making and breaking electric circuits and more particularly to automatic circuit breakers.

The object of the present invention is to provide an improved form of quick make and break' automatic electric circuit breaker of simple and economical construction and of small size and light weight.

Other objects and features o! the invention will be readily apparent to those skilled in the art from the following speciiications and the appendeddrawings illustrating certain preferred embodiments of the invention in which:

Figure 1 is a front elevational view ofean enclosed circuit breaker according to the present invention.

Figure 2 is a sectional view` taken on the line II-II of Figure 1 and showing the contacts in engaged position with a resetting position of certain of the parts being shown in dotted lines.

Figure 3 is a sectional View takenon the line III-III of Figure 2 but omitting the operating handle.

Figure 4 is a view similar to Figure 2 but showing the parts in overload tripped position.

Figure 5 is a View similar to Figure 2 but showing the parts in manually opened position.

Figure 6 is a detail exploded view showing the interconnection between the contact lever and loimetallicv element. y

The circuit breaker according to the present invention embodies a cup-shaped insulating base I having a metallic coverA 2 sealably secured thereto by studs 3 and with an insulating sheet 4 disposed back of the cover 2.

A generally S-shaped conducting connector 5 is disposed-at the forward end of the base I and extends through an opening 6 in the bottom I of the base to the exterior, and is rigidly held in position within the base by a stud Band its cooperatingnut 9, At its exteriorly disposed end the connector 5 carries a terminal stud II for securing a cable lead to the breaker, while a stationary contact surface I2 mounted upon the interior end thereof. A second conducting connector I3 is provided at the rear of the base I and comprises two elements I4'and I5 rigidly fastened together through g. rivet IB, with the element I4 being secured to the rear Wall II by a stud I8 and with the element I5 secured to the bottom of the base by a stud I9 to thereby rigidly maintain the connector in place. Element I4 extends through an opening 2| in the bottom 'I to the exterior and carries a terminal stud 22 at its outer end. A bimetatllic element 23 is rigidly welded or otherwise secured to the interior end of the connector element I4. A member 24 is disposed within a recess 25 in base I and is maintained therein by the defining walls of the recess (Cl. Zim- 116) and by a stud 26 threaded through the member. Thestud 26 is adapted to bear against the connector I3 and s'erves as an adjusting or calibrating means for the bimetallic element.

.A metallic frame or support 2l is provided within the base I spaced from the bottom "I of the base and held in position therein by rib formations on the side walls, A pin 28 is carried by the support 2l and provides, a pivot upon which are pivotally mounted a manual operator 29, having a handle portion 3l extending through an opening in the cover 2 to the exterior of the switch, a member 32 and a generally U-shaped contact lever or switch member 33 with the legs 34 and 35 thereof being disposed on opposite sides of the manual operator 23 and the member 32. A contact surface 38 is provided at the form ward end of the switch member 33 and is adapted to cooperate with stationary Contact I2 to complete a circuit therethrough. The pivot 28 is provided intermediate the ends of the switch member 33, and since the manual operator 23 and member 32 are mounted on this pivot, they are thus disposed intermediate the ends of the switch member. The operator 23 is provided at its under side with a depending portion 3l? carry ing a piovt 38 on which is mounted a spring guide 39. The switch member 33 carries a cross piece 4I between its legs 34 and 35 and having a slot 42 extending therethrough adapted to receive the free end` of the'guide member 39. A compression spring 43 is disposed about the guide 35 and is interposed between shoulder formations on the guide and the cross piece 4I for a purpose to be described. A spring 44 has one end secured to the lower part of pivotal member 32 and has its opa posite end iixed to a projection 45 on the support 2l. The operator 29 is cut away as at 4B and vthereby is adapted to be manually moved in the normal operation of the switch without affecting the pivotal member32. The depending portacts are engaged and is adapted to move the pivotal member 32 tion 3l of the operator 29 is disposed immediately adjacent the pivotal member 32 when the conand to be moved thereby under certain conditions to be hereinafter described. In the normal position of the pivotal member 32 the lower tip 4l thereof engages the free ex tremity of .the bimetallic element 23 and is retained in this position againstv the bias of spring u. A nexibieiead 4a interconnects the bimetauie' element 23 and the switch member to place the bimetallic element in series cir contacts. A generally L-shaped im member 49 is secured to the connecte J, 'rivet IG and is disposed between the ilexible lead 48 and the bimetallic element 23 1 to prevent short-circuiting therebetween.

A flange 5i on the support 2'I provides a stop adapted to engage a portion of the switch member 33 to define the es a l extent of pivotal movementJ thereof in a clockwise direction.

The operation ci' the switch will now be described.

From the on position of Figure 2, the initial movement of the operating handle 3l counter-.

lll-l becomes active to move the switch member 33 with a snap action in a clockwise direction to dis.-

engage the contacts, the switch member fia moving until it engages the limiting stop 5I. To efect re-engagement of contacts, the manual operator '2a is moved in the reverse direction and a reverse action oi the parts occurs.

ln the automatic operation of the parts, the occurrence of an overload current heats the bimetallic element 23 to bend it counter-clockwise to move it out of engagement with tip il of the pivotal member 32, whereupon the pivotal member moves counterclockwise under the bias of spring dll. The pivotal member in this movement engages the depending portion 3l of the manual operator 29 for positive movement thereof to carry the line of vforce of the spring d3 through the pivot 28 to move the switch member 32 to contacts disengaged position with a snap action. To reset,the breaker, the manual operator :le is moved clockwise to the dotted line position shown in Figure 2, the depending portion 3l in this resetting movement engaging and moving pivotal member 32 to the dotted line position of Figure 2 where its tip il will be in position to reengage the free end of the bimetallic element 23 upon release oi the manual operator. This resetting movement of the manual operator also effects a snap movement of the switch member 33 into contacts engaged position for the line' o force of spring i3 will be carried through the pivot all, the snap movement of the switch member occurring substantially simultaneously with the movement oi' the pivotal member 32 into the dotted line position. With release of the manual operator til, the tip fil moves toward reengagement with bimetal 23 under the bias of spring lll and if.. the condition or overload still exists, the parts will promptly disengage for the heat created by the iow of overload current will move having a movement relative to said switch member in the normal manual operation thereof, a relatively pivot therefor, 'including a resilient mem er interconnecting said actuating member and said switch member for moving said switch member with a snap movementrelative to said actuating member in response to manual movement of said actuating member, a pivotal member mounted within said breaker independently oi said switch member and on said relatively xed pivot and being pivotally movable independently of movement oi said actuating member, biasing means therefor, current responsive means engaging said pivotal member and being releasable therefrom upon the occurrence oi' an overload current, said pivotal member on. release moving to enect movement of said switch member.

2. In an automatic circuit breaker, a stationary contact, a movable contact, a switch member movable to eect movement of said movable contact to engaged and disengaged position, amanual operator having a movement relative to said switch member in the normal manual actuation thereof, a,relatively fixed pivot therefor, overcenter spring means for moving said switch member with a snap movement in response to movement of said manual operator, the movement of i said switch member being independent of the manual operator after the overcenter spring means passes through its dead center position, a vpivotal member mounted within said breaker independently of said switch member and on said relatively xed pivot, spring means having one end secured to said pivotal member and the other endthereof iixed, a series connected bimetallic member engaging said pivotal member and being releasable therefrom in response to predetermined current conditions, said pivotal member on release being movable by said spring means secured thereto to directly engage and positively actuate the manual operator to eiect snap movement of said switch member.

3. In an automatic electric circuit breaker, a stationary contact, a movable contact, a switch member movable to move said movable contact to effect circuit closure, means providing a relatively ixed pivot for said switch member, a manual operator mounted on said relatively fixed pivot and having a movement relative to said switch member in the normal actuation thereof, a link member interconnecting said manual operator the free end of the bimetalllc member 23 out of latching position and the parts will move again to "off position. It is seen, however, that the construction herein described permits the contacts to be held engaged, even though a condition of overload exists, by holding the manual' operator in the on position, to provide for a situation where the operator ilnds it necessary to maintain a circuit despite the existence of an overload current. f

While certain preferred embodiments 'o the invention have been specifically disclosed, it is understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpreand said switch member, a spring disposed on said link for quickly moving said switch member about its pivot in response to manual movement of said manual operator, said movement of the switch member being independent oi the manual operator after said spring has been moved through dead center position, a pivotal member mounted within the breaker independently of the switch member and oi the' manual operator, resilient means engaging an extremity of said pivotal member, a series connected bimetallic element engaging said pivotal member to hold said resilient means 4in a strained position and being releasable therefrom in response to a predetermined current, said pivotal member being movable by said resilient means upon disengagement to positively engage and move such manual operator to move said spring to eiect quick movement of said switch member.

4. In an automatic electric circuit breaker, `a stationary contact, a movable contact, means providing a relatively' iixecl pivot, a switch member mounted thereon and movable to move said stationary contact, a manual operator having a movement relative to said switch member in the normal manual actuation thereof, an overcenter .spring means operatively associated therewith and movable thereby to effect snap movement of said switch member, the movement of said switch member being independent of the manual operator after the overcenter spring means passes through its dead center position, a pivotal member mounted within the breaker independently of the switch member and on said relatively xed pivot, spring means having one end secured to said pivotal member and the opposite end thereof relatively fixed, a series connected bimetallic element engaging said pivotal member and being releasable therefrom in response to a predetermined current, said pivotal member upon disengagement being moved by said spring means to directly engage and effect movement of said manual operator to move said overcenter spring means to effect snap movement of the switch member to the olf position.

5. In an automatic electric circuit breaker, an enclosing base, a supporting member secured therein, a stationary contact, a movable contact, a pivot provided by said supporting member, a switch member mounted on said pivot and movable to move said movable contact for cooperation with said stationary contact to make and break an electric circuit thereto, a manual operator mounted on said pivot and having a movement relative to said switch member in the normal actuation thereof, overcenter spring means operatively interconnecting said manual operator and said switch member and adapted to move said switch member with a snap action in response to manual movement of the manual operator, the movement of said switch member being independent of the manual operatorafter the overcenter spring means passes through its dead center position, a pivotal member mounted within the enclosing base independently of the switch member, spring means having one end fixed to said supporting member and the opposite end thereof secured to said pivotal member, a bimetallic element having relatively fixed and free ends, a flexible lead connecting the free end of said bimetallic element to said switch member, said free end engaging said pivotal member to maintain said spring means in a strained position and being releasable therefrom in response to a predetermined current, said pivotal member upon disengagement moving under the bias of said spring means to positively engage and move said manual operator' for snap actuation of said switch member.

6. In an automatic electric circuit breaker, a stationary contact, a movable contact, means providing a relatively fixed pivot, a switch member mounted thereon and movable to move said movable contact into and out of engagement with said stationary contact, a manual operator mounted on said relatively fixed pivot and having a movement relative to said switch member .in the normal actuation thereof, overcenter spring means interconnecting said manual operator and said switch member for moving Said switch member with a snap action in response to manual movement of said manual operator, the movement of said switch member being independent of the manual operator after the overcenter spring means passes through its dead center position, a pivotal member mounted on said relatively fixed pivot, biasing means therefor, a

bimetallic element engaging said pivotal member and restraining it from movement by said biasing means, said bimetallic element releasing said pivotal member upon the occurrence of a predetermined current, said pivotal member upon release being movable by said biasing means to effect movement of said overcenter spring means, and means on said manual operator for positively moving said member into relatched engagement after such release.

7. In an automatic electric circuit breaker, a stationary contact, an elongated switch member having a contact surface adjacent to one end adapted to cooperate with said stationary con-.

tact, means providing a relatively fixed pivot for said switch member intermediate the end thereof, a manual operator mounted on said fixed pivot and having a movement relative to said switch member in the norm'al actuation thereof, means including a resilient member interconnecting said manual operator and the opposite end of said switch member for moving said switch member with Ya snap movement in response to manual movement of said manual operator, the movement of said switch member being independent of the manual operator after the resilient member has moved through dead center position, a pivotal member mounted on said relatively iixed pivot, spring means having one end secured to said pivotal member and the opposite end fixed, a series connected bimetallic element engaging said pivotal member to hold said spring means in a strained position, said bimetallic element being releasable therefrom upon the occurrence of an overload current, said pivotal member upon disengagement being movable by said spring means to positively move said manual operator.

8. In an automatic electric circuit breaker, an enclosing base, a supporting member secured therein, a stationary contact, a movable contact, a pivot provided by said supporting member, an elongated switch member mounted on said pivot and movable to move said movable contact for cooperation with said stationary contact, a manual operator mounted on said pivot and intermediate the ends of said switch member and having a movement relative to said switch member in the normal actuation thereof, overcenter spring means operatively interconnecting said manual operator and said switch member and adapted to move said switch member with a snap action in response to manual movement of the manual operator, the movement of said switch member being independent of the manual operator after the overcenter spring means passes through its dead center position, a pivotal member mounted on said relatively fixed pivot and intermediate the ends of said switch member, spring means having one end fixed to said supporting member and the opposite end secured to said pivotal member, a bimetallic element having relatively xed and free ends, a flexible lead connecting the free end of said bimetallic element to said switch member, said free end engaging said pivotal member to maintain the spring means in a strained position and being releasable therefrom in response,-

to a predetermined current, said pivotal member upon disengagement moving under the bias of said spring means to positively move said manual operator for snap actuation of said switch member, and means on said manual operator for p ositively moving said pivotal member into relatched engagement after said disengagement.

WILLIAM H. WOODS. 

